06/03/2015
Microsoft is currently pushing a "Critical" Windows update with the sole purpose of getting you to "Reserve your free copy of Windows 10"
Hang on a minute!
If you have Windows Update set to automatically apply critical updates (which is usually a good idea since "critical" is supposed to mean that there is a security vulnerability that has been discovered and patched) you may have found that you now have a program running in the Tool Tray ("Notification Area") of your Windows 7 or Windows 8.x computer that nags you to reserve your free upgrade to Windows 10.
I have a few problems with this.
First, labeling this update as "Important" and causing it to be automatically installed - getting everyone to upgrade to Windows 10 is important to Microsoft, not to me or anyone I know. Microsoft claims they are offering Windows 10 free to reduce fragmentation and get more people onto a single platform to simplify program development and support, but I have to question why a company that has been so militant about monetizing licensing and fees would give a "major" upgrade away unless Windows 10 provides them with an anticipated method of making even more money than selling upgrades would provide. The historically questionable ethics of Microsoft causes me to be nervous about this... Very nervous.
Removing the Windows 10 Nag about upgrading is pretty simple, but may cause problems down the road according to Microsoft. The nagging prompt is caused by update KB3035583 and removing it can be done by going into "Control Panel \ Programs and Features" then clicking on "View Installed Updates" Do a search for "KB3035583" and Uninstall that update.
HOWEVER - Microsoft's Joseph Conway has stated that this same update provides functionality that will possibly be used for other things in the future and has been quoted as saying "This update is applicable to your systems even if you're not planning to migrate to Windows 10, so don't think you can skip it."
So if I don't want to upgrade to Windows 10, my choices are to either deal with a useless programming running in the background to nag me to upgrade, or possible not be able to update my computer in the future ... ????
Most importantly, going along with this nag screen and reserving your copy of Windows 10 will enable an UPGRADE to Windows 10 from your current version. I have personally been working as a professional in IT since Windows 3.11 and I have been recommending for most of that time that Windows NOT be upgraded - if you want the new version, perform a CLEAN installation, not an upgrade. While I have seen some systems that were upgraded from one major version to another run acceptably, every single new release of Windows I have seen has been much more stable and much less problematic, on average, if a clean install is performed as opposed to an upgrade.
So, once again, Microsoft has decided to pull some antics that upset people for their own purposes and they're taking the stance of "What are you going to do about it? Switch to a different Operating System?"
With cloud applications becoming more and more important and only requiring a compatible browser, the importance of what Operating System you're running has been greatly reduced and appears to be likely to continue the reduction of importance. Microsoft's heavy-handed arrogance and belief that both the consumer and business sectors will willingly continue dealing with Microsoft forcing unwanted user experiences for the good of Microsoft just can't continue forever (ie: "Here, have this mobile device interface on your desktop. No, we don't care if it hurts productivity, we want you used to seeing the interface so you'll more willingly accept our mobile devices.")
Apple must be thrilled with all the business Microsoft is forcing in their direction.
KT
Update: You have to manually run Windows Update and right-click/Hide KB3035583 to prevent it from being automatically installed if you are set to automatically install "Important Updates"
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Update 6/9/2015:
There was some discussion and question about whether update KB3035583 was showing up as "important" (automatic installation) or "recommended" - I have just verified that a Windows 8.1 system is listing this update as "important" so it will be automatically installed if you have Windows Update configured that way.